Samples and data are analyzed from a longitudinal population study (1965 to 2007) that allows study of the risk factors and effects of diabetes mellitus. Long-term observations, up to 40 years, confirmed the profound effect of pre-existing diabetes or abnormal glucose tolerance in pregnancy on the risk of diabetes in the offspring. During the last year we have planned for new studies of pregant women and their children to assess long-term effects on the children of changes in weight and glycemia in the pregnant mothers.